Barclays Plc, the U.K.-based company behind the iPath family of ETNs as well as some of the most widely used fixed-income indexes, plans to sell its $6.1 billion, 19.6 percent stake in New York-based asset manager BlackRock back to BlackRock.

The $6.1 billion stake, made up of common shares and Series B convertible participating preferred stock, is valued in euros at $3.8 billion—a bit more than the $3.4 billion euros fair value at which the investment was written down in September 2011, Barclays said today in a press release.

Barclays said BlackRock filed regulatory paperwork today outlining the transaction, under which the British bank intends to exercise its option to sell its entire holding in BlackRock, the world’s biggest publicly traded asset manager.

The holding dates back to BlackRock’s 2009 acquisition of Barclays Global Investors—the company that first developed the iShares brand of exchange-traded funds.

iShares is the world’s largest ETF company, with some $466 billion in ETF assets, according to data compiled by IndexUniverse.